Comment 2 for bug 937249

StacktraceTop:
 composite_line (weights=0xa5f6800, n_x=2, n_y=2, dest=0xb54ec21c <Address 0xb54ec21c out of bounds>, dest_x=0, dest_end=0xb54ec258 <Address 0xb54ec258 out of bounds>, dest_channels=4, dest_has_alpha=1, src=0xa5fc880, src_channels=4, src_has_alpha=1, x_init=0, x_step=65536, src_width=16, check_size=0, color1=0, color2=0) at pixops.c:637
 pixops_process (dest_buf=0xb54ec21c <Address 0xb54ec21c out of bounds>, render_x0=0, render_y0=0, render_x1=16, render_y1=16, dest_rowstride=192, dest_channels=4, dest_has_alpha=1, src_buf=0xa5f8c00 "", src_width=16, src_height=16, src_rowstride=64, src_channels=4, src_has_alpha=1, scale_x=1, scale_y=1, check_x=0, check_y=0, check_size=0, color1=0, color2=0, filter=0xbfa64098, line_func=0xb624a360 <composite_line>, pixel_func=0xb624b650 <composite_pixel>) at pixops.c:1352
 _pixops_composite_real (overall_alpha=255, interp_type=PIXOPS_INTERP_BILINEAR, scale_y=1, scale_x=<optimized out>, src_has_alpha=1, src_channels=4, src_rowstride=64, src_height=16, src_width=16, src_buf=0xa5f8c00 "", dest_has_alpha=1, dest_channels=4, dest_rowstride=192, render_y1=<optimized out>, render_x1=<optimized out>, render_y0=<optimized out>, render_x0=<optimized out>, dest_buf=0xb54ec21c <Address 0xb54ec21c out of bounds>) at pixops.c:1810
 _pixops_composite (dest_buf=0xb54eae34 <Address 0xb54eae34 out of bounds>, dest_width=48, dest_height=48, dest_rowstride=192, dest_channels=4, dest_has_alpha=1, src_buf=0xa5f8c00 "", src_width=16, src_height=16, src_rowstride=64, src_channels=4, src_has_alpha=1, dest_x=26, dest_y=26, dest_region_width=16, dest_region_height=16, offset_x=26, offset_y=26, scale_x=1, scale_y=1, interp_type=PIXOPS_INTERP_BILINEAR, overall_alpha=255) at pixops.c:1877
 gdk_pixbuf_composite (src=0xa5bd838, dest=0xa5adf50, dest_x=26, dest_y=26, dest_width=16, dest_height=16, offset_x=<optimized out>, offset_y=<optimized out>, scale_x=1, scale_y=1, interp_type=GDK_INTERP_BILINEAR, overall_alpha=255) at gdk-pixbuf-scale.c:214